* test(opentui): launch the Windows preview entry through cmd.exe
The PowerShell preview installer preservation suite failed on every
nightly Windows run: the seeded qwen.cmd launcher printed nothing, and
the leftover batch child kept the file locked so teardown hit EBUSY.
PowerShell was only a way to run a .cmd from Node. Its `&` call plus
`exit $LASTEXITCODE` returned before the batch child wrote anything, so
run the entry through cmd.exe instead (`shell: true`).
PowerShell also writes its own startup cache under
%LOCALAPPDATA%\Microsoft\Windows\PowerShell. The fixture pointed
USERPROFILE at the home tree the assertions treat as installer-owned, so
every successful test failed on that cache. Point APPDATA and
LOCALAPPDATA outside the compared home.
* test(opentui): compare home files, not shell-created folders
With the launcher fixed, every case in the suite now reaches the
preservation assertion and fails on Windows because PowerShell creates
its own empty %USERPROFILE%\AppData folder shells on first run. Those
are the shell's account directories, not installer output.
Redirect APPDATA/LOCALAPPDATA outside the fixture home (so the startup
cache file stays out too) and compare only the home's file contents.
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Co-authored-by: yiliang114 <[email protected]>
